To find the number of kcal produced when 32.0 g of CH4 react, we need to first convert the given mass of CH4 to moles. To do this, we can use the molar mass of CH4, which is 16.0 g/mol.
32.0 g CH4 / 16.0 g/mol = 2.0 mol CH4
We can then use the balanced chemical equation to determine that for every mole of CH4 that reacts, 218 kcal are produced.
Therefore, when 32.0 g of CH4 react, 2.0 mol of CH4 react and produce 2.0 mol * 218 kcal/mol = <<2*218=436>>436 kcal.